/**
 * T13 · THE permanent cross-tenant tripwire (INV1). A green build MUST be impossible if
 * cross-tenant isolation regresses. Runs on every push/PR via .github/workflows/relay-tripwire.yml.
 * NEVER delete or skip this test.
 *
 * v0.9 unit variant (this file): in-memory port fakes; asserts every A→B path returns 403 —
 * onUpgrade, onReattach, a 1000-host fuzz, and aud-confusion. The v0.10 full-stack variant adds the
 * `cross-tenant-attempt` audit + alert assertions (needs T4 + T14, already exercised here via the
 * audit sink) and the real P1/P3 wiring.
 */
import { describe, it, expect, beforeEach } from 'vitest'
import { randomUUID } from 'node:crypto'
import { onUpgrade, onReattach, type EnforceDeps, type UpgradeContext } from '../../src/index.js'
import { resetDpopCacheForTest } from '../../src/capability/verify.js'
import type { StepUpPolicy } from '../../src/types.js'
import {
  setupP5SigningKey,
  makeHost,
  fakeHostRegistry,
  fakeSessionRegistry,
  fakeRevocationStore,
  fakeTokenBucket,
  fakeAuditSink,
  issueWithDpop,
  uuid,
} from '../_helpers.js'

const NOW = 1_700_000_000
const AUD_A = 'alice.term.example.com'
const AUD_B = 'bob.term.example.com'
const ORIGIN_A = `https://${AUD_A}`
const NEVER: StepUpPolicy = { required: false, maxAgeSeconds: Number.MAX_SAFE_INTEGER, requiredMethod: 'passkey' }

describe('PERMANENT TRIPWIRE — device A can never reach host B (INV1)', () => {
  let signingKey: CryptoKey
  const hostA = uuid()
  const hostB = uuid()
  let deps: EnforceDeps
  let audit: ReturnType<typeof fakeAuditSink>

  beforeEach(async () => {
    ;({ signingKey } = await setupP5SigningKey())
    resetDpopCacheForTest()
    audit = fakeAuditSink()
    deps = {
      hosts: fakeHostRegistry([makeHost('acct-A', hostA), makeHost('acct-B', hostB)]),
      sessions: fakeSessionRegistry([{ sessionId: 'sess-B', hostId: hostB, accountId: 'acct-B' }]),
      revocation: fakeRevocationStore(),
      buckets: fakeTokenBucket(),
      audit,
      stepUpPolicyFor: () => NEVER,
    }
  })

  function ctx(bundle: { raw: string; dpop: UpgradeContext['dpop'] }, over: Partial<UpgradeContext>): UpgradeContext {
    return {
      capabilityRaw: bundle.raw,
      originHeader: ORIGIN_A,
      expectedAud: AUD_A,
      requestedHostId: hostA,
      requiredRight: 'attach',
      remoteAddrHash: 'ip',
      activeSessionCount: 0,
      dpop: bundle.dpop,
      principal: null,
      ...over,
    }
  }

  it('onUpgrade with A token but requestedHostId = hostB → 403', async () => {
    const b = await issueWithDpop(signingKey, { accountId: 'acct-A', host: hostB, aud: AUD_A, now: NOW })
    const out = await onUpgrade(ctx(b, { requestedHostId: hostB }), deps, [ORIGIN_A], NOW)
    expect(out).toMatchObject({ ok: false, status: 403 })
  })

  it('onReattach with A token but a session owned by B → 403', async () => {
    const b = await issueWithDpop(signingKey, { accountId: 'acct-A', host: hostA, aud: AUD_A, now: NOW })
    const out = await onReattach({ ...ctx(b, {}), sessionId: 'sess-B' }, deps, [ORIGIN_A], NOW)
    expect(out).toMatchObject({ ok: false, status: 403 })
  })

  it('fuzz: 1000 random host_ids not owned by A → all 403', async () => {
    for (let i = 0; i < 1000; i++) {
      resetDpopCacheForTest()
      const foreign = randomUUID()
      const b = await issueWithDpop(signingKey, { accountId: 'acct-A', host: foreign, aud: AUD_A, now: NOW })
      const out = await onUpgrade(ctx(b, { requestedHostId: foreign }), deps, [ORIGIN_A], NOW)
      expect(out.ok).toBe(false)
      if (!out.ok) expect(out.status).toBe(403)
    }
  })

  it('aud confusion: A token replayed at bob.term.<domain> → 403/401', async () => {
    const b = await issueWithDpop(signingKey, { accountId: 'acct-A', host: hostA, aud: AUD_A, now: NOW })
    // present the A-audience token on B's subdomain
    const out = await onUpgrade(
      ctx(b, { expectedAud: AUD_B, requestedHostId: hostA, originHeader: ORIGIN_A }),
      deps,
      [ORIGIN_A],
      NOW,
    )
    expect(out.ok).toBe(false)
  })

  it('every A→B attempt records a deny (audit trail present, INV10)', async () => {
    const b = await issueWithDpop(signingKey, { accountId: 'acct-A', host: hostB, aud: AUD_A, now: NOW })
    await onUpgrade(ctx(b, { requestedHostId: hostB }), deps, [ORIGIN_A], NOW)
    expect(audit.events.every((e) => e.outcome === 'deny')).toBe(true)
    expect(audit.events.some((e) => e.action === 'cross-tenant-attempt')).toBe(true)
  })
})